Automatic name dialing is a term that is used to describe an application for making a telephone connection by speaking the name of the party to be connected to, instead of manually dialing the telephone number. Automatic name dialing is an application of voice recognition technology with additional features directed to telephones.
Automatic name dialing is a practical and interesting application of speech recognition to telephony systems. Existing name dialing and directory assistance systems include those sold by Nortel Communications and Nuance Communications. These systems have a simple and straightforward call flow. Error recovery is typically impossible with the user having to start all over again.
When a list of names to be recognized includes as many as 200,000 entries, and when telephone calls are received from all sorts of different channels and environments, the name recognition task becomes a very complex speech recognition problem. Unlike transcription tasks, such as the switchboard task, recognition of names poses a variety of different problems. For example, several problems arise from the fact that foreign names are hard to pronounce for speakers who are not familiar with the names and that there are no standardized methods for pronouncing proper names.
Typically, the overall accuracy of a name dialing system depends on a number of factors, including the speech recognition accuracy for multiple channels and noise environments, the number of homonyms and out-of-vocabulary entries in the name list, and the search speed when no language model can be used. The overall success rate of the system depends on factors such as, for example, the speech recognition accuracy, the call volume handling capability, the response speed and the user-friendliness of the user interface. Noise robustness is another very important factor, since many calls are typically made from noisy environments, such as from a car, cafeteria, airport, etc., and over different kinds of cellular and land-line telephone channels.
Furthermore, problems associated with large vocabulary name recognition systems in particular, in many cases, cannot be handled in a manner similar to small or medium vocabulary systems. Tasks such as digit or spelling recognition, or even small vocabulary (less than 100) name recognition applications, are more easily applied to small vocabulary systems.
The prior art in the name recognition area has typically focused on small vocabulary, speaker dependent and limited application environments. Thus, new approaches and algorithms are needed in order to achieve high recognition accuracy in the large vocabulary name recognition systems.